The present invention relates to a surface acoustic wave device (SAW device) to be used in a filter that is used in a mobile communication device or the like such as a mobile phone, and to a piezoelectric component such as piezoelectric membrane filter or the like, in particular, to a chip-size packaged piezoelectric component and a manufacturing method thereof.
A SAW device to be equipped in a mobile phone or the like requires a gap provided around a comb-shaped electrode (IDT electrode) of the SAW device.
Conventionally, a SAW device has been packed in which a SAW element chip is die-bonded on a ceramic case in a face-up state and its wiring is electrically connected by wire-bonding, and then a metallic cap is placed over the case and the matching face between the cap and case is seam-welded or sealed with solder.
Furthermore, recently, in order to downsize a SAW device, a small sized package SAW device is configured such that the SAW element chip is flip-chip-bonded (face down bonded) on a wiring substrate using Au bumps or other bumps, and sealing is carried out with a resin or the like.
Moreover, in order to reduce the size and height of a SAW device, there has been proposed a micro chip size package SAW device in which: a gap (hollow section) is formed in comb-shaped electrode sections; an entire piezoelectric wafer on the comb-shaped electrode side is sealed while maintaining this gap; an external connection electrode is formed; and then the sealed entire wafer is divided into individual SAW devices by dicing refer to Published Japanese Translation of PCT Application No. 2002-532934 (conventional example 1), and Japanese Unexamined Patent Publication No. 2004-147220 (conventional example 2).